Electric load regulator



Sept. 1950 A. J. KERCHER 2,521,171

ELECTRIC LOAD REGULATOR Filed June 15. 1948 3 Sheets-Sheet 1 IN VEN TOR.

HTTOBNEV Sept. 5, 1950 A. J. KERCl IER 2,521,171

ELECTRIC LOAD REGULATOR Filed June 15. 1948 3 Sheets-Sheet 2 LINE lGQOUND LINE 2 I INVEN TOR.

Sept. 5, 1950 A. J. KERCHER 2,521,171

ELECTRIC LOAD REGULATOR Filed June 15, 1948 3 Sheets-Sheet 3 LINE IGEOUND IN 'EN TOR.

Lona N0. 2

Patented Sept. 5, 1950 ELECTRIC LOAD REGULATOR Arthur J. Kercher,Berkeley, Calif assignmof one-halt to W. Wesley Hicks, San Francisco, I

Calif.

Application .iune 15, 1948, Serial No. 33,082

(Claims. (01. 171-97) This invention relates to the regulation ofelectric power loads.

There are many electric installations furnishing power for the operationof the usual household needs, such as electric lights, electric ranges,and electric water heaters. In addition, infrequent power consumption isrequired for household appliances, such as ironing and washing machines,fans, and refrigerators.

A persistent problem encountered in such installations is that the loadvaries between wide limits-from a very light load in the daytime when nocooking is done and hot water is little used, to a very heavy load atevening when the electric range and water heater are in use. Thiscondition is still further aggravated when electric room heaters providea part of the load.

It is one of the objects of this invention to make it possible toreducepart of the load without serious inconvenience to the user. Moreparticularly, it is an object of this invention to reduce the spaceheater load when the load demand for the remainder of the installationis apt to be heavy. 3

Since the period when intensive space heating is required is generallynot coincident with cooking, especially in mild climates such as on thePacific coast, this temporary reduction in space heating is easilytolerated.

Not only is the load factor much improved in this manner, but power isconserved. In periods of powershortages, this conservation is ofconsiderable importance.

In order to reduce the space heating load in accordance with thisinvention, the electromotive force supplying the space heaters isreduced. This can be eifectively done, especially when a three-wiresystem is used having a neutral or ground wire of intermediateelectromotive force with respect to the other two lines. Normally, thespace heating equipment is supplied from the two leads having a maximumelectromotive force between them. When the load for the rest of thesystem is heavy, the space heaters are connected between the neutralconductor and one of the other leads. With 240 volt three-wire systems,the reduced voltage is 120, thereby reducing the space heating load toone-fourth. It is not feasible to reduce the voltage applied to theremainder of the load, such as lighting or cooking; therefore, theinvention contemplates reducing the load where it may best be tolerated,as for space heating.

It is accordingly another object of this invention to make it possibleto reduce the power con z sumption of a part of the system withoutaffecting the remainder, when the demand is heavy, by reducing thevoltage across the said part.

This load reduction is made automatic, as for example when the currentsupplied to the remainder of the load reaches a definite high value; orthe reduction may be automatically efiected by the aid of a time switch,which operates to reduce the load at definite periods of the day ornight in which the remainder of the load is likely to be heavy.

It is still another object of this invention to provide a controlapparatus that effectively accomplishes these results.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of severalforms in which it may be embodied. Such forms are shown in the drawingsaccompanying and forming part of the present specification. These formswill now be described in detail, illustrating the general principles ofthe invention; but it is to be noted that such detailed description isnot to be taken in a limiting sense, since the scope of the invetnion isbest defined by the appended claims.

Referring to the drawings:

Figure l is a top plan view of an apparatus incorporating the invention;

Fig. 2 is a side view thereof;

Fig. 3 is a sectional view, taken along a plane corresponding to line 33of Fig. 1;

Fig. 4 is an enlarged, fragmentary sectional view, taken alon a planecorresponding to line i l of Fig. 1;

Fig. 5 is a view similar to Fig. 4, but showing an alternate position ofthe apparatus;

Fig. 6 is a wiring diagram illustrating the manner in which theapparatus can be utilized in a system; and

Fig. 7 is a similar wiring diagram of a modified form of the invention.

As shown most clearly in Fig. 6, a three-wire system is illustrated. Inthis system line i and line 2, as well as the ground connection, areintended to be supplied from a commercial source of electrical energy,such as a 240 volt system. The electromotive force between the lines 2and 2 may, for example, be 240 volts and the potential difierencebetween either line i or 2 and the ground connection is one-half ofthat, or 126 volts; I

Load No. 9, shown by rectangle i i, may comprise, in the usual householdinstallation, elec tricity consuming devices, such as a range, lights,

8imilarly,thatportiono!loadNo.21-epre-' sentedbyrectanzleIlmaybesuppliedtrom line 2 through connection It, the load l2,connection ti. risid switch ann ll, contact it on arm 3., stationarycontact 20, to line I.

WhenthedemandotloadNoJreachesspa-edeterminedvalue,currentcoils II and IIin combination movethecontactarms iltowardtheThecircuitfortbatportionottheloadrepresentedbyrectanalellcanbetrscediromlinei Similarly, the circuit for'thatportionoi'theloadtorectanglellcanbetncedtromlinetconnection'atothcpoeltionillilmtcdinm.4. In

'memberlhmwardiyandthebaliisreceived structure It to move thearms 24 and3' to Hit upper position, and this condition is illustrated in Figs. 1,2, a, and 4.

The relay structure it has two operating coils SI and II mounted on basel1 and opcratinz upon the tiltable armature I2. This armature I! ismounted for tilting upon the upright less [8 forming a part of themagnetic circuit for the relay. Thme legs are placed contizuously, andone of them may have a horiaontai projection to retain the armature 52on its bearing. The armature llcanbetiltedtothepositionoil'igaiand whencoil II is energized. Similarly, coil ll pulls the armature I! to theposition of Pig. 5.

As will be explained hereinafter, these coils II and II are onlymomentarily energized when contacts areiirstenzaged,soastopositionthearmature II in either oi the two positions.

The relay 40 controls the position of the switch armsllandll.Switcharmllisshownssmade of copper, with a flexible braided connectionI. and carriesthe contact 8'. Its left-hand end is similarly mounted ona post I which is connected to a terminal post II by the aid of whichthe connection 3i may be eil'ected. Arm i4 is entirely similar instructure to arm OI. Its leftfree position, the arms 24 and 80resiliently engage the stationary contacts 28 and 2!. These conanns 24and II, as by the'aid oi screws ll. pending below thishlock I, andcentrally thereof, isacammemberll. Thiscammemberisarrangedtobeoperatedtourxethearmsfl positionthearmcontacts-Il and l! areaaainstthestationarycontactsflandllr contacts are mounted upon ametallic ",extendingoyerthebracketsilandll havingdownwardlyextendinzleconnected terminalpostsilandll. Theseterminal maybemoimteduponthebasell,and oneotthetwotenninalsflandllmsybe nectedtothezroundline. I

Inordertourgethecaml2,andthereb arms2land3l,tothepositionotl"izs.2useismadeotansctuatorllmountedon thcarmature I2. Thisactuatormaybetormofahollowtubewithaspring-urged atitsuppcrendadaptedto mcthe surfaceI! otthecammember l2.

Inthefr'eepositionotl'ia.5,thesctuator isoutotcontactwiththeslopingHowever,whenthearmatureistiltedto tionotl'ig.4,theact1ntcrllur:es

arece'ss. Thisrecem l8 servesto apparatminthepcsitionotl'imdev II isde-enerzised. However, when coil Ienergised,thesctustorismovedquitcrcadily thepositicnotl'lmi.

Ooilllorllisenerzisedoniyiorsperiodmfllcienttobringthearmaturetoeitherthepositionotflitiorii.

armature 82 is brought to the position of Fig; 4. The circuit for thiscoil may be traced as follows: from line I, connection 28, coil 88,contacts 88 and II, contact arm 'II, connection- 12, contact 2i, contactarm I8, connection I9, to ground.

Contact 88 is mounted on a bracket I4 supported above the coil 58, andthe spring arm II is connected to a terminal post I5 shown in Fi 1.

Just as soon as the armature 52 reaches the attracted position of Fig.4, the spring arm II is urged to the left so that contacts 88 and I8 aredisconnected and coil 58 is thereby deenergized. Arm II is urged to theopen position by the insulation bar I! mounted on the armature 82. Theleft-hand end of this bar I5 engages the arcuate upper end I8 of springarm II and moves it toward the left.

The armature 82 stays in the position indicated in Fig. 4, the ballrestraint operating for this purpose in the recess 88. When this actiontakes place, load No. 2 is supplied with reduced voltage.

Should the load supplied to load No. i be sumciently reduced, thecontact arm I9 returns to the full-line position of Fig. 1. Under suchcircumstances coil 8| is energized through the following circuit: fromline I, connection 28, coil BI, contacts H8 and 11, connection I8,contact 28, arm I9, and connection I3 to the ground line. Contact H8 ismounted on a. bracket III similar to bracket 14. Contact TI ismounted onspring arm 19 that is connected to a terminal post on the base 81. Asbefore, as soon as the armature 52 reaches the position of Fig. 5, theenergizing circuit for coil BI is opened by engagement of the insulationbar 88 with the upper end of the arm 18. In this position, illustratedin Fig. 5, the load 2 is supplied with a higher voltage, and theapparatus stays in this position until arm I9 moves toward the dottedline position and causes, in a manner hereinbefore discussed, areduction in the voltage supplied to load No. 2.

The power required to move the armature 92 from the position of Fig. 4to the position of Fig. ii is relatively small, as it is merely requiredthat the actuator 66 be moved out of the recess t8.

However, movement of the armature 52 to the position of Fig. 4 requiresthat the spring arms 29 and 38 be flexed upwardly. Since the currentrelay R has delicately engaging contacts, which may chatter, it isadvantageous to provide another set of contacts that parallel thecontact hetween contact 2| and arm I9. This booster contact arrangementis illustrated most clearly in Figs. 1, 4 and 5.

Thus, a contact block BI is mounted on top of the bar 75. Cooperatingwith this contact block is a contact 86 mounted on a tiltable arm 82which is tiltably mounted near the left-hand edge of the bar i5. Thisarm 82 has a left-hand extension 93. This left-hand extension 83 is inthe path of a spring arm 94 that is mounted on the base 3? and connectedto a terminalpost 85.

In the low load position of Fig. 5, contact 98 may be out of engagementwith the contact bar 8!]. In this position, of course, the coil 58 isdeenergized because arm 09 is out of engagement with contact 20.However, as soon as arm i9 swings to the dotted line position of Fig. 6,coil 58 is energized, and the left-hand end of arm 92 engages the springarm 99. This engagement causes the arm 82 to rock in a clockwisedirection and to bring the contact 88 into engagement with the bar 8i.When this engagement occurs, the

contact between arm I8 and contact 2| is paralleled, and the circuit forcoil 88 is established even if contact arm I8 may vibrate in and out ofcontact. Under such circumstances, the circuit for coil 88 isestablished as follows: from line I, connection 28, coil 58, contacts 69and I8, arm II, connection H2, contact bar 8|, contact 88, arm 82, arm84, and connection 81, to the ground line.

The mode of operation of the system may now be briefly summarized by theaid 01 Fig. 6. Normally, while demand for load I is below apredetermined value, the connections are established as illustrated inthe full lines in the diagram.

Coil 5| has been momentarily energized through contacts H8 and I1 andthe apparatus is in the position of Fig. 5.

Upon a predetermined load being supplied to load No. I, contact arm I8swings to the dotted line position. A circuit is now established forcoil 58 and shortly thereafter contact is established between contact 86and contact bar 8|. The switch arms 24 and 38 move to the position ofFig. 4, causing a reduction in the load supplied to load No. 2. Thecircuit for coil 58 is then interrupted, the contacts 68 and I8 beingseparated.

In the form just discussed, the switching from high Voltage to lowvoltage for load No. 2 is effected by current relay R. However, thisswitching can be made to respond to a time switch mechanism, so that,during periods of heavy 1oad,

the low voltage can be connected to load No. 2.

Such an arrangement is illustrated diagrammatically in Fig. 7. In thisconnection, load No. i represented by rectangle II, is shown as suppliedfrom the three-wire system. A time switch mechanism 88 is illustrated,including a constant speed motor 89 supplied from line 2 to ground. Thismotor operates the time switch 98 which causes a connection to be madebetween lead 9| and lead 92 only during certain periods of the day.

The switching from high to low voltage is accomplished by the aid of anelectromagnetic switch mechanism 93 having a. coil 9i and the two switcharms and 96. These switch arms, in the normal position shown in thefigure, are in contact with the stationary contacts 91 and 88. Undersuch circumstances, the circuit for that portion of the load representedby rectangle i3 can be traced as follows: from line i, connection 99,load I3, connection i88, arm 95, contact 9?. and connection IM to line2. The circuit for load H can be traced from line 2, connection H82,load I2, connection i83, arm 98, contact 98, and connection 984, tolineI.

When the time switch 98 is in operation, coil 94 of the relay isenergized for moving arms 95 and 96 into engagement respectively withstationary contacts M5 and I 86. The coil 94 is energized from groundconnection I81, coil 94, connection 92, switch 98, and connection 9! toline 2.

Arms 95 and 96 are now in engagement respectively with contacts M5 and588. Under such circumstances load i3 is supplied as follows: line i,connection 98, load i3, connection (I88, arm 95, contact i85, connection081 to ground. Similarly, the circuit for load 92 can be traced asfollows: line 2, connection Q82, load i2, connection i83, arm 96,contact not and connection it? to ground. This corresponds to the lowvoltage connection.

The switch 98 thus controls the periods during which low voltage isutilized to supply load 2.

The inventor claims:

1. In a load regulating system for a three-wire source in which a lowvoltage and a high voltage for supplying electrical energ consumingloads are available: means for supplying a first load from the system;means for normally supplying a second load from the system with the highvoltage; and means for switching the second load to the low voltage inresponse to an increase of the first load to a predetermined value.

2. In a load regulating system for a three-wire source in which a lowvoltage and a high voltage for supplying two electrical energy consumingloads are available: means for supplying a first load from the system; aswitch for connecting the second of said loads either to the highvoltage or to the low voltage; a member for operating the switch andhaving two positions corresponding respectively to the low and highvoltage connections; electromagnets respectively for moving the memberto either position; and means responsive to a large value of the firstload for operating that electromagnet which causes the switch to assumethe low voltage position, and responsive to a reduced value of the firstload to operate that electromagnet which causes the switch to assume thehigh voltage position.

3. In a load regulating system for a three-wire source in which a lowvoltage and a high voltage for supplying two electrical energy consumingloads are available: means for supplying a first load from the system; acurrent relay operating in response to the current supplied to the firstload; and-means controlled by said relay for switching the second ofsaid loads either to the low voltage or the high voltage.

4. In a load regulating system for a three-wire source in which a lowvoltage and a high voltage for supplying two electrical energy consumingloads are available: means for supplying a first load from the system; acurrent relay having front and back contacts and operating in responseto the current supplied to the first load; a switch mechanism forconnecting the second of said loads either to the low voltage or thehigh voltage, and controlled by said relay; an operating member for theswitch having two positions corresponding to a high voltage position andto a low voltage position of the switch; electromagnets respectively formoving said member to either position; a control circuit operated by thefront contacts of the relay for energizing that electromagnet that movessaid member to the low voltage position, and including contacts openedby movement of the member to low voltage position; and a correspondingcontrol circuit for the other electromagnet operated by the backcontacts of the relay for energizing the other electromagnet andincluding contacts opened by movement of the member to high voltageposition.

5. The combinationas set forth in claim 4, with means for releasablylatching the member in low voltage position, including a cam carried bythe switch and a detent carried by the member and engaging the cam.

6. The-combination as set forth in claim 4, with a pair of contactsparalleling the front contacts of the relay; and means for causing thecontacts to engage upon an initial movement of the member to lowvoltages position.

7. In a control apparatus: a pivoted armature; a pair of electromagnetsfor moving the armature in opposite directions about its pivot; aresilient switch arm; means carried by the armature in move the switcharm to one position; a pivoted lever carried by the armature; a pair 0!contacts respectively on the lever and the armature; and means forurging the contacts together, upon movement of the armature in onedirection, comprising a resilient arm engaged by one end of the lever.

8. In a load regulating system for a three-wire source in which a lowvoltage and a high voltage for supplying electrical energy areavailable: means supplying a first load from the system; a current relayhaving front and back contacts and operated in response to the currentsupplied to the first load; a switch mechanism having two stablepositions for connecting a second load either to a high or a lowvoltage: a pair of electromagnet coil means for moving said switchmechanism to either stable position; circuit means operated in responseto the positioning of said switch mechanism for alternately conditioningone or the other of said electromagnet coil means; and a circuit foreach of said electromagnet coil means, either of which may be energizedaccording to the position of said relay.

9. In a load regulating system for a three-wire source in which a lowvoltage and a high voltage for supplying electrical energy areavailable: means supplying a first load from the system; a current relayhaving front and back contacts and operated in response to the currentsupplied to the first load; a switch mechanism having two stablepositions for connecting a second load either to a high or a lowvoltage; a pair of electromagnet coil means for moving said switchmechanism to either stable position; circuit means operated in responseto the positioning of said switch mechanism for alternately conditioning one or the other of said electromagnet coil means; a circuit foreach of said electromagnet coil means, either of which may be energizedaccording to the position of said relay; a pair of contacts parallelingthe front contacts of the relay; and means causing the contacts toengage upon an initial movement of the switching mechanism to lowvoltage position.

10. In a load regulating system for a threewire source in which a lowvoltage and a high voltage for supplying electrical energy areavailable: means for supplying a first load from the system; means fornormally supplying a second load from the system with the high voltage;electromagnetically operated switch means for switching the second loadto the low voltage; and a circuit for energizing said electromagnetineluding an armature adapted to close said circuit in response to anincrease of the first load to a predetermined value.

ARTHUR J. KERCHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STA'IES PATENIS 65 Number Name Date 514,398 Wiley Feb. 8, 18941,281,392 Kelly Oct. 15, 1918 1,743,115 Clark Jan. 14, 1930 1,938,405Tamsitt Dec. 5, 1933 70 2,199,639 Lee May I, 1940 2,388,839 Fry Nov. 13,1945

